No fire

[mvs57]

Have a 2000 4.3L mercruiser..will turn over but wont fire...no spark...change coil but still no spark....

 

[alldodge]

There are several 4.3's with all kinds of ignition systems, what is your serial number?

Is this a new to you boat?
What happened before it won't start?
What have you done to check for spark?

 

[ROY WILLIAMS]

Have a 2000 4.3L mercruiser will turn over but wont fire...no spark...change coil but still no spark....

use a voltmeter ... troubleshoot the coil voltage .
engine cranks and the engine does not run ... no spark ...distributor cap troubleshoot ...

 

[dubs283]

.change coil but still no spark....

Likely a thunderbolt ignition. A few reasons why no spark but most likely is ignition sensor in distributor. Need to verify no spark then follow the troubleshooting guide posted in the stickies

 

[mvs57]

Likely a thunderbolt ignition. A few reasons why no spark but most likely is ignition sensor in distributor. Need to verify no spark then follow the troubleshooting guide posted in the stickies

replaced that sensor still no spark...leaning towards ignition switch any input?

 

[ROY WILLIAMS]

replaced that sensor still no spark...leaning towards ignition switch any input?

use a voltmeter ...

 

[nola mike]

replaced that sensor still no spark...leaning towards ignition switch any input?

Yeah, follow the troubleshooting guide before throwing more parts at it.

How Mercruiser Thunderbolt ignition systems work.

Mercruiser Thunderbolt ignition systems. Mercruiser introduced the Thunderbolt IV onto their engines in 1982, alongside the introduction of the 1-R drives. The TB-IV system was used until the introduction of TB-V mid-way through 1996. Thunderbolt V was an improvement on an already exceptionally...

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